#include<iostream>
using namespace std;
class W3D{
int x,y,z;
public:
    W3D(int x=0, int y=0, int z=0) :x(x), y(y), z(z) 
    {
    	cout <<x;
    }
    W3D& operator= (W3D& w)
    {
        x=w.x; y=w.y; z=w.z; cout<<'='; return w;
    }
    W3D& operator +(W3D & t)
    {
        cout<<'+'; W3D suma(x+t.x, y+t.y, z+t.z);
	    return suma;
        }
};
 
int main()
{
	W3D a0, a1(1), a2(2);//
	a0 = a2 = a0 + a1 + a2;
}// kod daje wynik 012+1+3==     
// początek 012 wydaje mi się, że rozumiem. A dalej?
 
 

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